dev_uc_sync() and dev_mc_sync() are acquiring netif_addr_lock for
destination device of synchronization. Since netif_addr_lock is
already held at the time for source device, this triggers lockdep
deadlock warning.
There's no way this deadlock can happen so use spin_lock_nested() to
silence the warning.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-linus' of git://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (207 commits)
ARM: 7267/1: Remove BUILD_BUG_ON from asm/bug.h
ARM: 7269/1: mach-sa1100: fix sched_clock breakage
ARM: 7198/1: arm/imx6: add restart support for imx6q
ARM: restart: remove the now empty arch_reset()
ARM: restart: remove comments about adding code to arch_reset()
ARM: restart: lpc32xx & u300: remove unnecessary printk
ARM: restart: plat-samsung: remove plat/reset.h and s5p_reset_hook
ARM: restart: w90x900: use new restart hook
ARM: restart: Versatile Express: use new restart hook
ARM: restart: versatile: use new restart hook
ARM: restart: u300: use new restart hook
ARM: restart: tegra: use new restart hook
ARM: restart: spear: use new restart hook
ARM: restart: shark: use new restart hook
ARM: restart: sa1100: use new restart hook
ARM: 7252/1: restart: S5PV210: use new restart hook
ARM: 7251/1: restart: S5PC100: use new restart hook
ARM: 7250/1: restart: S5P64X0: use new restart hook
ARM: 7266/1: restart: S3C64XX: use new restart hook
ARM: 7265/1: restart: S3C24XX: use new restart hook
...
Fix up trivial conflict in arch/arm/mm/init.c due to removal of
memblock_init() clashing with the movement of the sorting of the meminfo
array.
* 'amba-modalias' of git://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm:
sound: aaci: Enable module alias autogeneration for AMBA drivers
watchdog: sp805: Enable module alias autogeneration for AMBA drivers
fbdev: amba: Enable module alias autogeneration for AMBA drivers
serial: pl011: Enable module alias autogeneration for AMBA drivers
serial: pl010: Enable module alias autogeneration for AMBA drivers
spi: pl022: Enable module alias autogeneration for AMBA drivers
rtc: pl031: Enable module alias autogeneration for AMBA drivers
rtc: pl030: Enable module alias autogeneration for AMBA drivers
mmc: mmci: Enable module alias autogeneration for AMBA drivers
input: ambakmi: Enable module alias autogeneration for AMBA drivers
gpio: pl061: Enable module alias autogeneration for AMBA drivers
dmaengine: pl330: Enable module alias autogeneration for AMBA drivers
dmaengine: pl08x: Enable module alias autogeneration for AMBA drivers
hwrng: nomadik: Enable module alias autogeneration for AMBA drivers
ARM: amba: Auto-generate AMBA driver module aliases during modpost
ARM: amba: Move definition of struct amba_id to mod_devicetable.h
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (185 commits)
powerpc: fix compile error with 85xx/p1010rdb.c
powerpc: fix compile error with 85xx/p1023_rds.c
powerpc/fsl: add MSI support for the Freescale hypervisor
arch/powerpc/sysdev/fsl_rmu.c: introduce missing kfree
powerpc/fsl: Add support for Integrated Flash Controller
powerpc/fsl: update compatiable on fsl 16550 uart nodes
powerpc/85xx: fix PCI and localbus properties in p1022ds.dts
powerpc/85xx: re-enable ePAPR byte channel driver in corenet32_smp_defconfig
powerpc/fsl: Update defconfigs to enable some standard FSL HW features
powerpc: Add TBI PHY node to first MDIO bus
sbc834x: put full compat string in board match check
powerpc/fsl-pci: Allow 64-bit PCIe devices to DMA to any memory address
powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit
offb: Fix setting of the pseudo-palette for >8bpp
offb: Add palette hack for qemu "standard vga" framebuffer
offb: Fix bug in calculating requested vram size
powerpc/boot: Change the WARN to INFO for boot wrapper overlap message
powerpc/44x: Fix build error on currituck platform
powerpc/boot: Change the load address for the wrapper to fit the kernel
powerpc/44x: Enable CRASH_DUMP for 440x
...
Fix up a trivial conflict in arch/powerpc/include/asm/cputime.h due to
the additional sparse-checking code for cputime_t.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1958 commits)
net: pack skb_shared_info more efficiently
net_sched: red: split red_parms into parms and vars
net_sched: sfq: extend limits
cnic: Improve error recovery on bnx2x devices
cnic: Re-init dev->stats_addr after chip reset
net_sched: Bug in netem reordering
bna: fix sparse warnings/errors
bna: make ethtool_ops and strings const
xgmac: cleanups
net: make ethtool_ops const
vmxnet3" make ethtool ops const
xen-netback: make ops structs const
virtio_net: Pass gfp flags when allocating rx buffers.
ixgbe: FCoE: Add support for ndo_get_fcoe_hbainfo() call
netdev: FCoE: Add new ndo_get_fcoe_hbainfo() call
igb: reset PHY after recovering from PHY power down
igb: add basic runtime PM support
igb: Add support for byte queue limits.
e1000: cleanup CE4100 MDIO registers access
e1000: unmap ce4100_gbe_mdio_base_virt in e1000_remove
...
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
sched/tracing: Add a new tracepoint for sleeptime
sched: Disable scheduler warnings during oopses
sched: Fix cgroup movement of waking process
sched: Fix cgroup movement of newly created process
sched: Fix cgroup movement of forking process
sched: Remove cfs bandwidth period check in tg_set_cfs_period()
sched: Fix load-balance lock-breaking
sched: Replace all_pinned with a generic flags field
sched: Only queue remote wakeups when crossing cache boundaries
sched: Add missing rcu_dereference() around ->real_parent usage
[S390] fix cputime overflow in uptime_proc_show
[S390] cputime: add sparse checking and cleanup
sched: Mark parent and real_parent as __rcu
sched, nohz: Fix missing RCU read lock
sched, nohz: Set the NOHZ_BALANCE_KICK flag for idle load balancer
sched, nohz: Fix the idle cpu check in nohz_idle_balance
sched: Use jump_labels for sched_feat
sched/accounting: Fix parameter passing in task_group_account_field
sched/accounting: Fix user/system tick double accounting
sched/accounting: Re-use scheduler statistics for the root cgroup
...
Fix up conflicts in
- arch/ia64/include/asm/cputime.h, include/asm-generic/cputime.h
usecs_to_cputime64() vs the sparse cleanups
- kernel/sched/fair.c, kernel/time/tick-sched.c
scheduler changes in multiple branches
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (106 commits)
perf kvm: Fix copy & paste error in description
perf script: Kill script_spec__delete
perf top: Fix a memory leak
perf stat: Introduce get_ratio_color() helper
perf session: Remove impossible condition check
perf tools: Fix feature-bits rework fallout, remove unused variable
perf script: Add generic perl handler to process events
perf tools: Use for_each_set_bit() to iterate over feature flags
perf tools: Unify handling of features when writing feature section
perf report: Accept fifos as input file
perf tools: Moving code in some files
perf tools: Fix out-of-bound access to struct perf_session
perf tools: Continue processing header on unknown features
perf tools: Improve macros for struct feature_ops
perf: builtin-record: Document and check that mmap_pages must be a power of two.
perf: builtin-record: Provide advice if mmap'ing fails with EPERM.
perf tools: Fix truncated annotation
perf script: look up thread using tid instead of pid
perf tools: Look up thread names for system wide profiling
perf tools: Fix comm for processes with named threads
...
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
cpu: Export cpu_up()
rcu: Apply ACCESS_ONCE() to rcu_boost() return value
Revert "rcu: Permit rt_mutex_unlock() with irqs disabled"
docs: Additional LWN links to RCU API
rcu: Augment rcu_batch_end tracing for idle and callback state
rcu: Add rcutorture tests for srcu_read_lock_raw()
rcu: Make rcutorture test for hotpluggability before offlining CPUs
driver-core/cpu: Expose hotpluggability to the rest of the kernel
rcu: Remove redundant rcu_cpu_stall_suppress declaration
rcu: Adaptive dyntick-idle preparation
rcu: Keep invoking callbacks if CPU otherwise idle
rcu: Irq nesting is always 0 on rcu_enter_idle_common
rcu: Don't check irq nesting from rcu idle entry/exit
rcu: Permit dyntick-idle with callbacks pending
rcu: Document same-context read-side constraints
rcu: Identify dyntick-idle CPUs on first force_quiescent_state() pass
rcu: Remove dynticks false positives and RCU failures
rcu: Reduce latency of rcu_prepare_for_idle()
rcu: Eliminate RCU_FAST_NO_HZ grace-period hang
rcu: Avoid needlessly IPIing CPUs at GP end
...
* 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
memblock: Reimplement memblock allocation using reverse free area iterator
memblock: Kill early_node_map[]
score: Use HAVE_MEMBLOCK_NODE_MAP
s390: Use HAVE_MEMBLOCK_NODE_MAP
mips: Use HAVE_MEMBLOCK_NODE_MAP
ia64: Use HAVE_MEMBLOCK_NODE_MAP
SuperH: Use HAVE_MEMBLOCK_NODE_MAP
sparc: Use HAVE_MEMBLOCK_NODE_MAP
powerpc: Use HAVE_MEMBLOCK_NODE_MAP
memblock: Implement memblock_add_node()
memblock: s/memblock_analyze()/memblock_allow_resize()/ and update users
memblock: Track total size of regions automatically
powerpc: Cleanup memblock usage
memblock: Reimplement memblock_enforce_memory_limit() using __memblock_remove()
memblock: Make memblock functions handle overflowing range @size
memblock: Reimplement __memblock_remove() using memblock_isolate_range()
memblock: Separate out memblock_isolate_range() from memblock_set_node()
memblock: Kill memblock_init()
memblock: Kill sentinel entries at the end of static region arrays
memblock: Add __memblock_dump_all()
...
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep/waitqueues: Add better annotation
lockdep, bug: Exclude TAINT_OOT_MODULE from disabling lock debugging
lockdep: Print lock name in lockdep_init_error()
init/main.c: Execute lockdep_init() as early as possible
lockdep, kmemcheck: Annotate ->lock in lockdep_init_map()
lockdep, rtmutex, bug: Show taint flags on error
lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep
lockdep: Always try to set ->class_cache in register_lock_class() lockdep_init_map()
* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timer: Use debugobjects to catch deletion of uninitialized timers
timer: Setup uninitialized timer with a stub callback
debugobjects: Extend to assert that an object is initialized
debugobjects: Be smarter about static objects
nr_frags can be 8 bits since 256 is plenty of fragments. This allows it to be
packed with tx_flags.
Also by moving ip6_frag_id and dataref (both 4 bytes) next to each other we can
avoid a hole between ip6_frag_id and frag_list on 64 bit systems.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SFQ as implemented in Linux is very limited, with at most 127 flows
and limit of 127 packets. [ So if 127 flows are active, we have one
packet per flow ]
This patch brings to SFQ following features to cope with modern needs.
- Ability to specify a smaller per flow limit of inflight packets.
(default value being at 127 packets)
- Ability to have up to 65408 active flows (instead of 127)
- Ability to have head drops instead of tail drops
(to drop old packets from a flow)
Example of use : No more than 20 packets per flow, max 8000 flows, max
20000 packets in SFQ qdisc, hash table of 65536 slots.
tc qdisc add ... sfq \
flows 8000 \
depth 20 \
headdrop \
limit 20000 \
divisor 65536
Ram usage :
2 bytes per hash table entry (instead of previous 1 byte/entry)
32 bytes per flow on 64bit arches, instead of 384 for QFQ, so much
better cache hit ratio.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dave Taht <dave.taht@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds a new ndo_get_fcoe_hbainfo() call in
net_device_ops for FCoE protocol stack.
If supported by the underlying device, the FCoE protocol
stack will call this to get device specific information
from the underlying device.
This information will then be utilized by the FCoE protocol
stack to register Fiber Channel HBA attributes with the
Fiber Channel Management Service via Fabric Device
Management Interface (FDMI) as per the T11 FC-GS
specification.
Changes in v2:
- As per comments from David Miller aligning the parameters
of the ndo_get_fcoe_hbainfo()
Signed-off-by: Neerav Parikh <Neerav.Parikh@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The nfcid1 is the NFC-A identifier.
It is exported as an attribute of the target info
(returned as a response to NFC_CMD_GET_TARGET).
Signed-off-by: Ilan Elias <ilane@ti.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
All implementations have been converted to implement set_rxnfc
instead.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define special location values for RX NFC that request the driver to
select the actual rule location. This allows for implementation on
devices that use hash-based filter lookup, whereas currently the API is
more suited to devices with TCAM lookup or linear search.
In ethtool_set_rxnfc() and the compat wrapper ethtool_ioctl(), copy
the structure back to user-space after insertion so that the actual
location is returned.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SMSC generation 4 LAN chips integrate an IEEE 802.3 ethernet physical layer.
The ethernet driver for this family of devices needs to access the SMSC PHY
registers and bit-fields.
So, this patch moves these constants to a place where it can be used for both
the PHY and LAN drivers.
Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 1e39f384bb ("evm: fix build problems") makes the stub version
of security_old_inode_init_security() return 0 when CONFIG_SECURITY is
not set.
But that makes callers such as reiserfs_security_init() assume that
security_old_inode_init_security() has set name, value, and len
arguments properly - but security_old_inode_init_security() left them
uninitialized which then results in interesting failures.
Revert security_old_inode_init_security() to the old behavior of
returning EOPNOTSUPP since both callers (reiserfs and ocfs2) handle this
just fine.
[ Also fixed the S_PRIVATE(inode) case of the actual non-stub
security_old_inode_init_security() function to return EOPNOTSUPP
for the same reason, as pointed out by Mimi Zohar.
It got incorrectly changed to match the new function in commit
fb88c2b6cb: "evm: fix security/security_old_init_security return
code". - Linus ]
Reported-by: Jorge Bastos <mysql.jorge@decimal.pt>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While it's not too late fix the recently added RQLEN diag extension
to report rqlen and wqlen in the same way as TCP does.
I.e. for listening sockets the ack backlog length (which is the input
queue length for socket) in rqlen and the max ack backlog length in
wqlen, and what the CINQ/OUTQ ioctls do for established.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Fix indentation of sock_diag*() calls. -DaveM ]
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a routine that dumps memory-related values of a socket.
It's made as an array to make it possible to add more stuff
here later without breaking compatibility.
Since v1: The SK_MEMINFO_ constants are in userspace
visible part of sock_diag.h, the rest is under __KERNEL__.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The headers check complains it should include the linux/types.h
withing, thus add this one.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Properly toss existing components around the ifdef __KERNEL__
and include the header into the header-y target.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the new macro and struct names in xt_ecn.h, and put the old
definitions into a definition-forwarding ipt_ecn.h.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Prepare the ECN match for augmentation by an IPv6 counterpart. Since
no symbol dependencies to ipv6.ko are added, having a single ecn match
module is the more so welcome.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Unlike all of the other cpuid bits, the TSC deadline timer bit is set
unconditionally, regardless of what userspace wants.
This is broken in several ways:
- if userspace doesn't use KVM_CREATE_IRQCHIP, and doesn't emulate the TSC
deadline timer feature, a guest that uses the feature will break
- live migration to older host kernels that don't support the TSC deadline
timer will cause the feature to be pulled from under the guest's feet;
breaking it
- guests that are broken wrt the feature will fail.
Fix by not enabling the feature automatically; instead report it to userspace.
Because the feature depends on KVM_CREATE_IRQCHIP, which we cannot guarantee
will be called, we expose it via a KVM_CAP_TSC_DEADLINE_TIMER and not
KVM_GET_SUPPORTED_CPUID.
Fixes the Illumos guest kernel, which uses the TSC deadline timer feature.
[avi: add the KVM_CAP + documentation]
Reported-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
We currently have two ways to account traffic in netfilter:
- iptables chain and rule counters:
# iptables -L -n -v
Chain INPUT (policy DROP 3 packets, 867 bytes)
pkts bytes target prot opt in out source destination
8 1104 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
- use flow-based accounting provided by ctnetlink:
# conntrack -L
tcp 6 431999 ESTABLISHED src=192.168.1.130 dst=212.106.219.168 sport=58152 dport=80 packets=47 bytes=7654 src=212.106.219.168 dst=192.168.1.130 sport=80 dport=58152 packets=49 bytes=66340 [ASSURED] mark=0 use=1
While trying to display real-time accounting statistics, we require
to pool the kernel periodically to obtain this information. This is
OK if the number of flows is relatively low. However, in case that
the number of flows is huge, we can spend a considerable amount of
cycles to iterate over the list of flows that have been obtained.
Moreover, if we want to obtain the sum of the flow accounting results
that match some criteria, we have to iterate over the whole list of
existing flows, look for matchings and update the counters.
This patch adds the extended accounting infrastructure for
nfnetlink which aims to allow displaying real-time traffic accounting
without the need of complicated and resource-consuming implementation
in user-space. Basically, this new infrastructure allows you to create
accounting objects. One accounting object is composed of packet and
byte counters.
In order to manipulate create accounting objects, you require the
new libnetfilter_acct library. It contains several examples of use:
libnetfilter_acct/examples# ./nfacct-add http-traffic
libnetfilter_acct/examples# ./nfacct-get
http-traffic = { pkts = 000000000000, bytes = 000000000000 };
Then, you can use one of this accounting objects in several iptables
rules using the new nfacct match (which comes in a follow-up patch):
# iptables -I INPUT -p tcp --sport 80 -m nfacct --nfacct-name http-traffic
# iptables -I OUTPUT -p tcp --dport 80 -m nfacct --nfacct-name http-traffic
The idea is simple: if one packet matches the rule, the nfacct match
updates the counters.
Thanks to Patrick McHardy, Eric Dumazet, Changli Gao for reviewing and
providing feedback for this contribution.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
irqdomain support is used in interrupt controller drivers that may not
have device tree support but only need the basic HW->Linux irq
translation. Rather than having each of these implement their own IRQ
domain, allow them to use the simple ops.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rob Herring <robherring2@gmail.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Conflicts:
net/bluetooth/l2cap_core.c
Just two overlapping changes, one added an initialization of
a local variable, and another change added a new local variable.
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to accommodate a 64K buffer we need 64K/PAGE_SIZE plus one more page
in order to allow for a buffer which does not start on a page boundary.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Export the NAT definitions to userspace. So far userspace (specifically,
iptables) has been copying the headers files from include/net. Also
rename some structures and definitions in preparation for IPv6 NAT.
Since these have never been officially exported, this doesn't affect
existing userspace code.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This partially reworks bc01befdcf
which added userspace expectation support.
This patch removes the nf_ct_userspace_expect_list since now we
force to use the new iptables CT target feature to add the helper
extension for conntracks that have attached expectations from
userspace.
A new version of the proof-of-concept code to implement userspace
helpers from userspace is available at:
http://people.netfilter.org/pablo/userspace-conntrack-helpers/nf-ftp-helper-POC.tar.bz2
This patch also modifies the CT target to allow to set the
conntrack's userspace helper status flags. This flag is used
to tell the conntrack system to explicitly allocate the helper
extension.
This helper extension is useful to link the userspace expectations
with the master conntrack that is being tracked from one userspace
helper.
This feature fixes a problem in the current approach of the
userspace helper support. Basically, if the master conntrack that
has got a userspace expectation vanishes, the expectations point to
one invalid memory address. Thus, triggering an oops in the
expectation deletion event path.
I decided not to add a new revision of the CT target because
I only needed to add a new flag for it. I'll document in this
issue in the iptables manpage. I have also changed the return
value from EINVAL to EOPNOTSUPP if one flag not supported is
specified. Thus, in the future adding new features that only
require a new flag can be added without a new revision.
There is no official code using this in userspace (apart from
the proof-of-concept) that uses this infrastructure but there
will be some by beginning 2012.
Reported-by: Sam Roberts <vieuxtech@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).
Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.
So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
ensure that the newly onlined CPU does not proceed with its corresponding
per-cpu spinlock unlocked.
To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
initialized in the lock_init() code, all future updates to it are done in
the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
unlocking the per-cpu locks.
The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).
The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).
Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.
By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.
Debugged-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
This event counts the number of reference core cpu cycles.
Reference means that the event increments at a constant rate which
is not subject to core CPU frequency adjustments. The event may
not count when the processor is in halted (low power) state.
As such, it may not be equivalent to wall clock time. However,
when the processor is not halted state, the event keeps
a constant correlation with wall clock time.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1323559734-3488-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
to record the state of SACK/FACK and DSACK for better readability and maintenance.
Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/clocksource: Fix kernel-doc warnings
rtc: m41t80: Workaround broken alarm functionality
rtc: Expire alarms after the time is set.
